Area code 564

From Wikipedia, the free encyclopedia
Jump to: navigation, search

564 is an area code for the state of Washington covering all of Western Washington, including Seattle. It is an overlay plan for area codes 206, 253, 360 and 425. It was originally proposed and approved in 2000, but was not implemented until July 29, 2017. Initially it will only be assigned in the 360 area, but will expand to other area codes in the region as they exhaust.[1]

In 1999, area code 564 was proposed as an overlay of area code 360, which serves areas of Western Washington outside of the Seattle Tacoma metropolitan area. This version of the overlay was slated for implementation on July 29, 2000. Later, the Washington Utilities and Transportation Commission (WUTC) determined that the actual increase in need for new numbers in 360 had fallen short of projections, and postponed the overlay until at least February 2001.

In May 2000, the commission projected that the metropolitan Seattle area codes (206, 253 and 425) would also soon exhaust their number pools, and expanded the 564 plan to include those areas as well. By the summer, however, this was determined to be not immediately necessary. The overlay was then planned for application on October 20, 2001.

On August 22, 2001, the WUTC announced that, due to increased efficiency in the reuse of the existing number pool, the immediate need for the new area code had subsided. Part of this was also attributed to a downturn in the telecommunications sector. The commission put off implementation until no earlier than October 20, 2002.

Since the development of the initial plan for the area code, the WUTC and the NANPA have rebuffed the telephone companies' request for a new area code and instead directed them to actively share and efficiently use the number blocks already assigned. This mainly refers to the practice of number pooling, which divides telephone exchange prefixes for more efficient allocation as 10 blocks of 1,000 numbers, instead of assigning a prefix's whole numbering space (10,000 numbers) to one carrier in the one rate centre.

The WUTC has taken further steps to decrease the need for new number blocks in 360 and 509 and head off the need for new area codes, including aggressive reclamation of unused and underused number blocks and exchanges. The introduction of mandatory local and wireless number portability (a prerequisite for number pooling) has also served to stem the demand for new numbers and thus new area codes.[2]

According to the WUTCs estimate as of March 2014, the earliest projection for any Western Washington area code to be exhausted is 2018, for area code 360. None of the other codes are expected to exhaust before 2025.[2]

On July 29, 2017, 10-digit dialing became mandatory for all local calls in Western Washington, replacing the use of 7-digit dialing.[3] Beginning September 30, 2017, telephone numbers with the area code 564 will be issued in the existing number plan area 360. When the other codes in western Washington exhaust, 564 numbers will also be assigned in those areas.


  1. ^ "New area code coming to western Washington" (Press release). Washington Utilities and Transportation Commission. May 19, 2016. Retrieved May 19, 2016. 
  2. ^ a b Washington State Area Codes and Numbering Issues, Washington Utilities and Transportation Commission, March 2016, retrieved 2016-12-30 
  3. ^ "In the Matter of the Implementation of the 564 Numbering Plan Area: Order Adopting Implementation Plan (PDF)". Washington Utilities and Transportation Commission. May 20, 2016. Retrieved January 30, 2017. 

External links[edit]

Washington area codes: 206, 253, 360, 425, 509, 564
North: 236/778, 250, 604
West: Pacific Ocean, 250 Area code 564 (overlays 360; will also overlay 206, 253, and 425 when necessary) East: 509
South: 503/971
British Columbia area codes: 236, 250, 604, 778
Oregon area codes: 458, 503, 541, 971